Float-type flowmeter

Abstract

A float-type flowmeter and method for measuring the flow of fluids, incorporates a measuring tube through which measuring tube the fluid can flow against the force of gravity and which is provided with a float capable of moving at least in the direction of the flow, and an acquisition unit capable of tracking the movement of the float, with a motion signal corresponding to the movement of the float being transmissible to a diagnostic unit in which diagnostic unit an oscillation signal corresponding to the oscillation amplitude of the float can be derived from the motion signal and an error or alarm signal can be generated when, for a predefined length of time, the oscillation signal falls below a minimum setpoint value. To permit a prediction of the future progression of the condition of the float-type flowmeter, the flowmeter provides the capability to feed the motion signal corresponding to the movement of the float to a predictive evaluation unit, to compare the motion signal in the predictive evaluation unit with the values anticipated for the movement of the float as a function of the lift of the float, and, on the basis of deviations of the motion signal from the anticipated values, to cause the predictive evaluation unit to generate and output data on the current state of the float-type flowmeter as well as on the probable, expected future condition of the float-type flowmeter.

What is claimed is:  
     
       1. A float-type flowmeter for measuring the flow of a fluid comprising 
       a measuring tube through which a fluid can flow against the force of gravity;  
       a float in said tube, said float being movable in the tube at least in the direction of the fluid flow and having a density greater than that of the fluid so that as a function of the fluid flow rate, the float will be suspended in the tube at a particular height level determined by the equilibrium between the hydrodynamic force of the fluid impinging on the float and the weight or buoyancy of the float;  
       an acquisition unit positioned adjacent to the measuring tube for tracking the movement of the float in said tube and producing a corresponding motion signal, and  
       a predictive evaluation unit connected to receive said motion signal, said predictive evaluation unit including means for storing an anticipated motion signal corresponding to the anticipated movement of the float and means for comparing the motion signal with the anticipated motion signal and, on the basis of deviations of the motion signal from the anticipated motion signal, providing data on the probable, expected future state of the float-type flowmeter in order to alert an user of the float-type flowmeter to an impending malfunction of the float-type flowmeter.  
     
     
       2. The float-type flowmeter as in  claim 1 , wherein said predictive evaluation unit performs said comparison on the basis of the height level of the float. 
     
     
       3. The float-type flowmeter as in  claim 1  or  2 , wherein said predictive evaluation unit compares the oscillation frequency of the motion signal with the oscillation frequency of the anticipated motion signal. 
     
     
       4. The float-type flowmeter as in  claim 1  or  2 , wherein said predictive evaluation unit compares the motion signal with the anticipated motion signal in terms of the pattern of the motion signal. 
     
     
       5. The float-type flowmeter as in  claim 1  or  2 , wherein said predictive evaluation unit stores the motion signal at least for a predefined length of time and, on the basis of time-related changes of the motion signal, provides data relative to the probable, expected future state of the float-type flowmeter. 
     
     
       6. The float-type flowmeter as in  claim 1  or  2 , wherein the predictive evaluation unit includes means responsive to the motion signal for providing information relative to the movement of the float along the flow direction of the fluid and/or to the movement of the float perpendicular to the flow direction of the fluid and/or to the rotational movement of the float. 
     
     
       7. The float-type flowmeter as in  claim 6 , wherein said predictive evaluation unit includes means which as part of the comparison of the motion signal with the anticipated motion signal, make individually separate comparisons relative to the movement of the float along the flow direction of the fluid and/or to the movement of the float perpendicular to the flow direction of the fluid and/or to the rotational movement of the float. 
     
     
       8. The float-type flowmeter as in  claim 1  or  2 , wherein said predictive evaluation unit performs a historical analysis for the motion signal. 
     
     
       9. The float-type flowmeter as in  claim 1  or  2 , wherein said predictive evaluation performs a Fourier analysis on the motion signal. 
     
     
       10. A method for predicting the state of a float-type flowmeter measuring the flow of a fluid, comprising the steps of 
       providing a measuring tube through which fluid can flow against the force of gravity;  
       providing a float in the tube that is movable in the tube at least in the direction of the fluid flow;  
       tracking the movement of the float in the tube and producing a motion signal in response thereto;  
       obtaining and storing an anticipated motion signal corresponding to the anticipated movement of the float;  
       comparing the motion signal to said anticipated motion signal to produce deviations between the two;  
       from said deviations providing information on the probable, expected future state of the float-type flowmeter, and  
       depending on the probable, expected future state of the float-type flowmeter alerting an user of the float-type flowmeter to an impending malfunction of the float-type flowmeter.  
     
     
       11. A method as in  claim 10 , wherein the comparison of the motion signal corresponding to the movement of the float with the anticipated motion signal is made as a function of the height level of the float. 
     
     
       12. The method as in  claim 10  or  11  including the step of comparing the oscillation frequency of the motion signal with the oscillation frequency of the anticipated motion signal. 
     
     
       13. The method as in  claim 10  or  11  including the step of comparing the pattern of the motion signal with the pattern of the anticipated motion signal. 
     
     
       14. The method as in  claim 10  or  11  including the steps of storing the motion signal for at least a predefined length of time and, from time-related changes of the motion signal, providing information on the probable, expected future state of the float-type flowmeter. 
     
     
       15. The method as in  claim 10  or  11  including the step of providing with the aid of the motion signal, information relative to the movement of the float along the flow direction of the fluid and/or to the movement of the float perpendicular to the flow direction of the fluid and/or to the rotational movement of the float. 
     
     
       16. The method as in  claim 15 , including the step of making as part of the comparison of the motion signal with the anticipated motion signal, individually separate comparisons relative to the movement of the float along the flow direction of the fluid and/or to the movement of the float perpendicular to the flow direction of the fluid and/or to the rotational movement of the float. 
     
     
       17. The method as in  claim 10  or  11  including the step of displaying the information on the probable, expected future state of the float-type flowmeter in scalar, vectorial or graphic form. 
     
     
       18. The method as in  claim 10  or  11  including the step of subjecting the motion signal to a historical or statistical evaluation. 
     
     
       19. The method as in  claim 10  or  11  including the step of subjecting the motion signal to a fast Fourier transform operation. 
     
     
       20. A method for predicting the state of a float-type flowmeter measuring the flow of a fluid, comprising the steps of 
       providing a measuring tube through which fluid can flow against the force of gravity;  
       providing a float in the tube that is movable in the tube at least in the direction of the fluid flow;  
       tracking the movement of the float in the tube and producing a motion signal in response thereto;  
       obtaining and storing an anticipated motion signal corresponding to the anticipated movement of the float;  
       comparing the oscillation frequency of the motion signal to the oscillation frequency of said anticipated motion signal to produce deviations between the two, and  
       from said deviations providing information on the probable, expected future state of the float-type flowmeter.